U.S. patent application number 10/446015 was filed with the patent office on 2004-12-02 for toner processes.
This patent application is currently assigned to Xerox Corporation. Invention is credited to Farrugia, Valerie M., Hawkins, Michael S..
Application Number | 20040241568 10/446015 |
Document ID | / |
Family ID | 33131554 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040241568 |
Kind Code |
A1 |
Farrugia, Valerie M. ; et
al. |
December 2, 2004 |
Toner processes
Abstract
A toner process comprising heating a mixture of a latex and a
colorant, which heating is accomplished below about the glass
transition temperature, Tg, of polymer contained in the latex;
cooling; and subsequently adding a methacrylate polymer solution;
adjusting the pH of the mixture resulting to permit the
methacrylate polymer to precipitate on said mixture of latex and
said colorant; and wherein resulting product is heated above about
the glass transition temperature, Tg, of said latex polymer.
Inventors: |
Farrugia, Valerie M.;
(Oakville, CA) ; Hawkins, Michael S.; (Cambridge,
CA) |
Correspondence
Address: |
PATENT DOCUMENTATION CENTER
XEROX CORPORATION
100 CLINTON AVE., SOUTH, XEROX SQUARE, 20TH FLOOR
ROCHESTER
NY
14644
US
|
Assignee: |
Xerox Corporation
|
Family ID: |
33131554 |
Appl. No.: |
10/446015 |
Filed: |
May 27, 2003 |
Current U.S.
Class: |
430/137.14 |
Current CPC
Class: |
G03G 9/0804
20130101 |
Class at
Publication: |
430/137.14 |
International
Class: |
G03G 009/08 |
Claims
What is claimed is:
1. A toner process comprising heating a mixture of a latex and a
colorant, which heating is accomplished below about the glass
transition temperature, Tg, of polymer contained in the latex;
cooling; and subsequently adding a methacrylate polymer solution;
adjusting the pH of the mixture resulting to permit the
methacrylate polymer to precipitate on said mixture of latex and
said colorant.
2. A process in accordance with claim 1 wherein said latex contains
a polyester polymer, and wherein the pH is adjusted to about 7.
3. A process in accordance with claim 2 wherein said latex contains
a sulfonated polyester, and wherein the pH is adjusted to about
7.
4. A process in accordance with claim 1 wherein said latex polymer
is a polyester of the formula 2wherein Y is an alkali metal, X is a
glycol, and n and m each represent the number of segments.
5. A process in accordance with claim 4 wherein said alkali metal
is sodium, or potassium.
6. A process in accordance with claim 4 wherein said glycol is an
alkylene glycol.
7. A process in accordance with claim 6 wherein said glycol is an
aliphatic glycol of neopentyl glycol, ethylene glycol, propylene
glycol, butylene glycol, pentylene glycol, propanediol,
1,2-propanediol, diethylene glycol, dipropylene glycol, or
optionally mixtures thereof.
8. A process in accordance with claim 4 wherein said m and said n
each represent a number of from about 10 to about 30.
9. A process in accordance with claim 4 wherein the weight average
molecular weight (M.sub.w) of said polyester is from about 2,000
grams per mole to about 100,000 grams per mole, the number average
molecular weight (Mn) is from about 1,000 grams per mole to about
50,000 grams per mole, and the polydispersity thereof is from about
2 to about 18 as measured by gel permeation chromatography.
10. A process in accordance with claim 1 wherein said methacrylate
is a butylmethacrylate-(2-dimethylaminoethyl)
methacrylate/methylmethacrylate copolymer.
11. A process in accordance with claim 10 wherein said polymer
ratio of said segments is 1:2:1.
12. A process in accordance with claim 11 wherein said polymer
ratio is about 25 percent:50 percent:25 percent; about 33
percent:33 percent:33 percent; about 0 percent:25 percent:75
percent; or about 0 percent:0 percent:100 percent.
13. A process in accordance with claim 1 wherein said methacrylate
is a
butylmethacrylate-(2-dimethylaminoethyl)methacrylate-methylmethacrylate
copolymer (1:2:1) containing (2-dimethylaminoethyl) methacrylate,
butyl methacrylate and methyl methacrylate with a mean molecular
weight, M.sub.w of from about 125,000 to about 175,000.
14. A process in accordance with claim 1 wherein said methacrylate
is present in an amount of from about 1 to about 10 percent by
weight.
15. A process in accordance with claim 1 wherein said methacrylate
is present in an amount of from about 3 to about 7 percent by
weight.
16. A process in accordance with claim 1 wherein said methacrylate
is a butylmethacrylate-(dimethylaminoethyl
methacrylate/methylmethacrylate copolymer present in an amount of
from about 1 to about 10 percent by weight.
17. A process in accordance with claim 1 wherein said methacrylate
is a butylmethacrylate-(dimethylaminoethyl)
methacrylate/methylmethacrylate copolymer present in an amount of
from about 3 to about 7 percent by weight.
18. A process in accordance with claim 1 wherein said pH is from
about 8 to about 12.
19. A process in accordance with claim 1 wherein said pH above 7 is
from about 10 to about 11.
20. A process in accordance with claim 1 wherein the pH of the
resulting mixture after heating is from about 2 to about 5, and
which pH is increased to from about 9 to about 12 subsequent to the
addition of said methacrylate.
21. A process in accordance with claim 1 wherein the pH of the
resulting mixture after heating is from about 2 to about 4 and
which pH is increased to from about 10 to about 12 subsequent to
the addition of said methacrylate.
22. A process in accordance with claim 20 wherein the pH is
increased by the addition of a base.
23. A process in accordance with claim 22 wherein the base is an
alkali metal hydroxide.
24. A process in accordance with claim 22 wherein the base is
sodium hydroxide.
25. A process in accordance with claim 1 further including adding a
wax to said latex and said colorant mixture.
26. A process in accordance with claim 25 wherein said wax a
polypropylene, a polyethylene, or mixtures thereof.
27. A process in accordance with claim 25 wherein said wax is a
polyethylene.
28. A process in accordance with claim 25 wherein said wax
possesses a low weight average molecular weight M.sub.w of from
about 1,000 to about 20,000.
29. A process in accordance with claim 1 wherein there is further
included a coagulant.
30. A process in accordance with claim 1 wherein there is further
included a coagulant of zinc acetate.
31. A process in accordance with claim 1 wherein said heating is
from about 35.degree. C. to about 55.degree. C.
32. A process in accordance with claim 1 further including a second
heating above the latex resin Tg subsequent to said addition of
said methacrylate polymer.
33. A process in accordance with claim 32 wherein said heating is
from about 70.degree. C. to about 95.degree. C. and wherein
coalescence results for said latex resin, said colorant and said
methacrylate, and which methacrylate is present on the surface of
said resulting toner.
34. A process in accordance with claim 33 wherein said polymer is
present in an amount of from about 80 to about 98 percent by
weight, and said colorant is present in an amount of from about 2
to about 20 percent by weight of the toner.
35. A process in accordance with claim 1 wherein the colorant is a
pigment.
36. A process in accordance with claim 1 wherein said latex polymer
is selected from the group consisting of poly(styrene-butadiene),
poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene),
poly(ethyl methacrylate-butadiene), poly(propyl
methacrylate-butadiene), poly(butyl methacrylate-butadiene),
poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene),
poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene),
poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl
methacrylate-isoprene), poly(ethyl methacrylate-isoprene),
poly(propyl methacrylate-isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl
acrylate-isoprene), poly(propyl acrylate-isoprene), poly(butyl
acrylate-isoprene); poly(styrene-propyl acrylate),
poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid),
poly(styrene-butadiene-m- ethacrylic acid),
poly(styrene-butadiene-acrylonitrile-acrylic acid),
poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl
acrylate-methacrylic acid), poly(styrene-butyl
acrylate-acrylononitrile), and poly(styrene-butyl
acrylate-acrylononitrile-acrylic acid).
37. A process in accordance with claim 1 wherein the colorant is
carbon black, cyan, yellow, magenta, or mixtures thereof, and the
toner resulting is from about 2 to about 25 microns in volume
average diameter, and wherein there is optionally added to the
surface of the formed toner metal salts, metal salts of fatty
acids, silicas, metal oxides, or mixtures thereof, each in an
amount of from about 0.1 to about 10 percent by weight of the
obtained toner.
38. A process in accordance with claim 4 wherein said polyester
resin is poly(1,2-propylene-sodio 5-sulfoisophthalate).
39. A process in accordance with claim 4 wherein said polyester
resin is polyneopentylene-sodio 5-sulfoisophthalate polyester.
40. A toner process comprising heating a mixture of a latex and a
colorant, which heating is accomplished below about the glass
transition temperature, Tg, of polymer contained in the latex;
cooling; and subsequently adding a methacrylate polymer solution;
adjusting the pH of the mixture resulting to permit the
methacrylate polymer to precipitate on said mixture of latex and
said colorant; and wherein resulting product is heated above about
the glass transition temperature, Tg, of said latex polymer.
41. A toner process comprising heating a mixture of a latex and a
colorant, which heating is accomplished below about the glass
transition temperature, Tg, of polymer contained in the latex;
cooling; and subsequently adding a methacrylate polymer solution;
adjusting the pH of the mixture resulting to permit said
methacrylate to form on said mixture of said latex and said
colorant; and wherein resulting product is heated above about the
glass transition temperature, Tg, of said latex polymer.
Description
PENDING APPLICATIONS AND PATENTS
[0001] Illustrated in copending application U.S. Ser. No.
10/261,129, entitled Toners and Developers, filed Sep. 27, 2002,
the disclosure of which is totally incorporated herein by
reference, is a toner comprising at least one binder in an amount
of from about 85 to about 99 percent by weight, at least one
colorant in an amount of from about 0.5 to about 15 percent by
weight, and calcium stearate in an amount of from about 0.05 to
about 2 percent by weight, and wherein following triboelectric
contact with carrier particles, the toner has a charge Q measured
in femtocoulombs per particle diameter D measured in microns (Q/D)
of from about -0.1 to about -1 fC/.mu.m with a variation during
development of from about 0 to about 0.25 fC/.mu.m, and wherein the
distribution is substantially unimodal and possesses a peak width
of from about 0.1 fC/.mu.m to about 0.5 fC/.mu.m and the toner
possesses a charge to mass M, as measured in grams, ratio (Q/M) of
from about -25 to about -70 .mu.C/gram with variation of Q/M during
development of from about 0 to about 15 .mu.C/gram.
[0002] In U.S. Pat. No. 6,132,924, the disclosure of which is
totally incorporated herein by reference, there is illustrated a
process for the preparation of toner comprising mixing a colorant,
a latex, and two coagulants, followed by aggregation and
coalescence, and wherein one of the coagulants may be polyaluminum
chloride.
[0003] Illustrated in copending application U.S. Ser. No.
10/086,063, entitled Toner Processes, filed Mar. 1, 2002, the
disclosure of which is totally incorporated herein by reference, is
a process comprising heating a latex, a colorant dispersion, a
polytetrafluoroethylene dispersion, and an organo metallic
complexing component.
[0004] Illustrated in U.S. Pat. No. 5,945,245, the disclosure of
which is totally incorporated herein by reference, is a process for
the preparation of toner compositions comprising:
[0005] (i) preparing an emulsion latex comprised of sodio
sulfonated polyester resin particles of from about 5 to about 500
nanometers in size diameter, by heating said resin in water at a
temperature of from about 65.degree. C. to about 90.degree. C.;
[0006] (ii) preparing a pigment dispersion in water by dispersing
in water from about 10 to about 25 weight percent of sodio
sulfonated polyester, and from about 1 to about 5 weight percent of
pigment;
[0007] (iii) adding the pigment dispersion to a latex mixture
comprised of sulfonated polyester resin particles in water with
shearing, followed by the addition of an alkali halide in water
until aggregation results, as indicated by an increase in the latex
viscosity of from about 2 centipoise to about 100 centipoise;
[0008] (iv) heating the resulting mixture at a temperature of from
about 45.degree. C. to about 55.degree. C., thereby causing further
aggregation and enabling coalescence, resulting in toner particles
of from about 4 to about 9 microns in volume average diameter and
with a geometric distribution of less than about 1.3; and
optionally
[0009] (v) cooling the product mixture to about 25.degree. C. and
followed by washing and drying.
[0010] Disclosed in copending application U.S. Ser. No. 10/260,377,
entitled Toner Processes, filed Sep. 27, 2002, the disclosure of
which is totally incorporated herein by reference, is a process
comprising heating a sulfonated polyester resin latex and a
colorant below about the glass transition temperature (Tg) of the
sulfonated polyester resin, adding a metal stearate to the
resulting slurry, and isolating the product, and wherein the
heating generates an alkyl carboxylate metal salt component
ionically attached to the surface of the product.
[0011] In embodiments of the present invention there may be
selected the appropriate components, and processes of the above
copending applications and patents.
BACKGROUND
[0012] The present invention is directed to a toner process, and
more specifically, to chemical toner processes which involve the
aggregation and fusion of latex, colorant like pigment or dye, a
metal oxide, a commercially available methacrylate copolymer,
available from Rohm American Inc. as EUDRAGIT.TM., and optional
additive particles.
[0013] More specifically, in embodiments the present invention
relates to toner processes wherein there results a toner with a
positive charge, triboelectric charge stability to a variety of
environmental conditions, excellent developer aging
characteristics, reduced excessive negative C-zone charge to
thereby provide excellent toner relative humidity (RH) sensitivity,
excellent flowing toners and toners free or substantially free of
undesirable clumping, and wherein a toner slurry is admixed with
the EUDRAGIT.TM. (EEPO) and wherein after pH adjustments the EEPO
is precipitated on the toner surface and forms a thin film or layer
of a positively charged polymer of EEPO around the toner
surface.
[0014] The toners generated with the processes of the present
invention can be selected for copying and printing processes,
including high speed highlight color systems, trilevel color
xerography, color processes, and for a number of known imaging
processes, and which toners can provide, for example, high quality
colored images, including excellent developed custom color images
with excellent image resolution, acceptable signal-to-noise ratio,
and image uniformity. Also, the toners obtained with the processes
illustrated herein can be specifically selected for digital imaging
systems and processes.
REFERENCES
[0015] In xerographic systems, especially color systems, small
sized toners of, for example, from about 2 to about 10 microns can
be of value to the achievement of high image quality for process
color applications; obtaining a low image pile height to eliminate,
or minimize image feel and avoid paper curling after fusing. Paper
curling can exist in xerographic color processes primarily because
of the presence of relatively high toner coverage as a result of
the application of three to four color toners. During fusing,
moisture escapes from the paper due to high fusing temperatures of
from about 120.degree. C. to about 200.degree. C. In the situation
wherein only one layer of toner is selected, such as in one-color
black or highlight color xerographic applications, the amount of
moisture driven off during fusing can be reabsorbed by the paper,
and the resulting print remains relatively flat with minimal paper
curl. In process color where toner coverage is high, the relatively
thick toner plastic covering on the paper can inhibit the paper
from reabsorbing the moisture, and cause substantial paper curling.
These and other imaging shortfalls and problems are avoided or
minimized with the toners and processes of the present
invention.
[0016] Also, it may be useful to select certain toner particle
sizes, such as from about 2 to about 10 microns, with a high
colorant, especially pigment loading, such as from about 4 to about
15 percent by weight of toner, so that the mass of toner selected
for attaining the desired optical density and color gamut can be
reduced to eliminate or minimize paper curl. Lower toner mass also
can ensure the achievement of image uniformity. However, higher
pigment loadings often adversely affect the charging behavior of
toners. For example, the charge levels may be too low for proper
toner development or the charge distributions may be too wide and
toners of wrong charge polarity may be present. Furthermore, higher
pigment loadings may also result in the sensitivity of toner
charging behavior to charges in environmental conditions, such as
temperature and humidity. Toners prepared in accordance with the
processes of the present invention minimize, or avoid these
disadvantages in embodiments.
[0017] There is illustrated in U.S. Pat. No. 4,996,127, the
disclosure of which is totally incorporated herein by reference, a
toner of associated particles of secondary particles comprising
primary particles of a polymer having acidic or basic polar groups
and a coloring agent. The polymers selected for the toners of the
'127 patent can be prepared by an emulsion polymerization method,
see for example columns 4 and 5 of this patent. In column 7 of this
'127 patent, it is indicated that the toner can be prepared by
mixing the required amount of coloring agent and optional charge
additive with an emulsion of the polymer having an acidic or basic
polar group obtained by emulsion polymerization. In U.S. Pat. No.
4,983,488, the disclosure of which is totally incorporated herein
by reference, there is disclosed a process for the preparation of
toners by the polymerization of a polymerizable monomer dispersed
by emulsification in the presence of a colorant and/or a magnetic
powder to prepare a principal resin component, and then effecting
coagulation of the resulting polymerization liquid in such a manner
that the particles in the liquid after coagulation have diameters
suitable for a toner. In U.S. Pat. No. 4,797,339, the disclosure of
which is totally incorporated herein by reference, there is
disclosed a process for the preparation of toners by resin
emulsion; and in U.S. Pat. No. 4,558,108, the disclosure of which
is totally incorporated herein by reference, there is disclosed a
process for the preparation of a copolymer of styrene and butadiene
by specific suspension polymerization processes.
[0018] Polyester based chemical toners substantially free of
encapsulation are illustrated in U.S. Pat. No. 5,593,807, the
disclosure of which is totally incorporated herein by reference,
wherein there is disclosed a process for the preparation of a toner
comprised of a sodio sulfonated polyester resin and pigment, and
wherein the aggregation and coalescence of resin particles is
mediated with an alkali halide. Other U.S. patents that may be of
interest, the disclosures of which are totally incorporated herein
by reference, are U.S. Pat. Nos. 5,853,944; 5,843,614; 5,840,462;
5,604,076; 5,648,193; 5,658,704; and 5,660,965.
[0019] In U.S. Pat. No. 4,837,100, there is illustrated, for
example, an electrophotographic developer comprising a carrier,
toner particles positively chargeable by friction with the carrier,
fine particles of hydrophilic alumina and fine particles of one of
tin oxide, hydrophobic silica and titanium dioxide and wherein the
hydrophilic alumina fine particles are present in an amount of from
about 0.1 to 3 percent by weight based on the weight of toner
particles.
[0020] Emulsion/aggregation/coalescence processes for the
preparation of toners are illustrated in a number of Xerox
Corporation patents, the disclosures of each of which are totally
incorporated herein by reference, such as U.S. Pat. No. 5,290,654,
U.S. Pat. No. 5,278,020, U.S. Pat. No. 5,308,734, U.S. Pat. No.
5,370,963, U.S. Pat. No. 5,344,738, U.S. Pat. No. 5,403,693, U.S.
Pat. No. 5,418,108, U.S. Pat. No. 5,364,729, and U.S. Pat. No.
5,346,797; and also of interest may be U.S. Pat. Nos. 5,348,832;
5,405,728; 5,366,841; 5,496,676; 5,527,658; 5,585,215; 5,650,255;
5,650,256; 5,501,935; 5,723,253; 5,744,520; 5,763,133; 5,766,818;
5,747,215; 5,827,633; 5,853,944; 5,804,349; 5,840,462; 5,869,215;
5,863,698; 5,902,710; 5,910,387; 5,916,725; 5,919,595; 5,925,488;
5,858,601, and 5,977,210. The appropriate components and processes
of the above Xerox Corporation patents can be selected for the
processes of the present invention in embodiments thereof.
[0021] With respect to the references, only a part thereof has been
selected and this part may or may not be fully representative of
the teachings or disclosures.
SUMMARY
[0022] It is a feature of the present invention to provide toner
processes with many of the advantages illustrated herein.
[0023] In another feature of the present invention there are
provided simple and economical processes for the preparation of
black and colored toner compositions with excellent colorant
dispersions, thus enabling the achievement of excellent color print
quality; and a simple and economical chemical process for the
preparation of toner compositions.
[0024] Additionally, another feature of the present invention
resides in a process capable of delivering differing toner
morphology particles, such as spherically shaped toner
particles.
[0025] Moreover, in another feature of the present invention there
are provided emulsion, aggregation, coalescence processes wherein,
for example, the positively charging toner obtained has
incorporated during the process, that is, for example, prior to or
subsequent to aggregation and coalescence, a methacrylate
copolymer, available from Rohm American Inc. as EUDRAGIT.TM..
[0026] Aspects of the present invention relate to a toner process
comprising heating a mixture of a latex and a colorant, which
heating is accomplished below about the glass transition
temperature, Tg, of polymer contained in the latex; cooling; and
subsequently adding a methacrylate polymer solution; adjusting the
pH of the mixture resulting to permit the methacrylate polymer to
precipitate on said mixture of latex and said colorant; A toner
process comprising heating a mixture of a latex and a colorant,
which heating is accomplished below about the glass transition
temperature, Tg, of polymer contained in the latex; cooling; and
subsequently adding a methacrylate polymer solution; adjusting the
pH of the mixture resulting to permit the methacrylate polymer to
precipitate on said mixture of latex and said colorant; and wherein
resulting product is heated above about the glass transition
temperature, Tg, of said latex polymer; a toner process comprising
heating a mixture of a latex and a colorant, which heating is
accomplished below about the glass transition temperature, Tg, of
polymer contained in the latex; cooling; and subsequently adding a
methacrylate polymer solution; adjusting the pH of the mixture
resulting to permit said methacrylate to form on said mixture of
said latex and said colorant; and wherein resulting product is
heated above about the glass transition temperature, Tg, of said
latex polymer; a process wherein the latex is a latex emulsion
comprised of resin, water, and an ionic surfactant, and wherein the
colorant mixture is a dispersion containing a colorant, water, and
an ionic surfactant; a process wherein there is selected for the
ionic surfactant a nonionic surfactant; a process wherein the
methacrylate copolymer, available from Rohm American Inc. as
EUDRAGIT.TM., is selected in an amount of from about 1 to about 10
percent by weight of the toner components; a process wherein the
methacrylate copolymer, available from Rohm American Inc. as
EUDRAGIT.TM., is selected in an amount of from about 3 to about 7
percent by weight; a process wherein each of the surfactants is
selected in an amount of from about 1 to about 10 percent by weight
based on the toner components amounts; a process wherein there can
optionally be added to the toner mixture a second latex, and which
latex is comprised of submicron resin particles suspended in an
aqueous phase containing an ionic surfactant, and wherein the
second latex is optionally selected in an amount of from about 10
to about 40 percent by weight of the initial latex; a process
wherein the temperature below about the latex resin Tg is from
about 40.degree. C. to about 60.degree. C., thereby resulting in
toner aggregates, and the temperature above about the latex resin
Tg is from about 75.degree. C. to about 97.degree. C.; a process
wherein the temperature at which the aggregation is accomplished
controls the size of the aggregates, and wherein the toner isolated
is from about 2 to about 15 microns in volume average diameter; a
process wherein the colorant is a pigment; a process wherein the
latex contains a polyester, such as polyester SPE2, available from
Hercules Chemical; a toner and processes thereof wherein the
polyester is of the formula 1
[0027] wherein Y is an alkali metal, X is a glycol, and n and m
each represent the number of segments; a toner wherein the
polyester is a sodiosulfonated polyester; a toner wherein the
polyester is present in an amount of from about 80 to about 98
percent by weight of the toner, the colorant is present from an
amount of from about 2 to about 20 percent by weight of the toner,
and wherein the methacrylate copolymer, available from Rohm
American Inc. as EUDRAGIT.TM., is present on the surface of the
toner in an amount of from about 2 to about 7 percent by weight,
and wherein the total of all the toner components is about 100
percent; a toner wherein the polyester resin contains from about
0.1 to about 5 percent by weight of sulfonated groups; a toner
wherein the methacrylate copolymer, available from Rohm American
Inc. as EUDRAGIT.TM., primarily functions to enhance the toner
triboelectric charge and reduce the toner relative humidity
sensitivity; a process for the preparation of toner comprising
mixing a methacrylate copolymer, available from Rohm American Inc.
as EUDRAGIT.TM., with a latex and a colorant mixture comprised of
colorant, and an ionic surfactant; heating the resulting mixture
below about the glass transition temperature (Tg) of the latex
resin; heating above about the Tg of the latex resin; or
alternatively adding the methacrylate copolymer, available from
Rohm American Inc. as EUDRAGIT.TM., particles, which particles can
function as a charge enhancing additive, after the aforementioned
two heatings and optionally isolating the toner, and wherein the
methacrylate copolymer resides on the surface of the toner; a
process wherein the latex is a latex emulsion comprised of resin,
water, and an ionic surfactant, and wherein the colorant mixture is
a dispersion containing a colorant, water, and an ionic surfactant;
a process wherein there is selected for the ionic surfactant a
nonionic surfactant; a process wherein each of the surfactants is
selected in an amount of from about 1 to about 7 percent by weight
based on the toner component amounts; a process wherein there can
optionally be added to the mixture illustrated a second latex, and
which latex is comprised of resin particles suspended in an aqueous
phase containing an ionic surfactant, and wherein the second latex
is selected in an amount of from about 15 to about 25 percent by
weight of the initial latex; a process wherein the temperature
about below the latex resin Tg is from about 40.degree. C. to about
60.degree. C., thereby resulting in toner aggregates, and the
temperature above about the latex resin Tg is from about 77.degree.
C. to about 95.degree. C.; a process wherein the latex resin is
selected from the group consisting of poly(styrene-butadiene),
poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene),
poly(ethyl methacrylate-butadiene), poly(propyl
methacrylate-butadiene), poly(butyl methacrylate-butadiene),
poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene),
poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene),
poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl
methacrylate-isoprene), poly(ethyl methacrylate-isoprene),
poly(propyl methacrylate-isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl
acrylate-isoprene), poly(propyl acrylate-isoprene), poly(butyl
acrylate-isoprene); poly(styrene-propyl acrylate),
poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid),
poly(styrene-butadiene-methacrylic acid), poly(styrene-butadiene-a-
crylonitrile-acrylic acid), poly(styrene-butyl acrylate-acrylic
acid), poly(styrene-butyl acrylate-methacrylic acid),
poly(styrene-butyl acrylate-acrylononitrile), and
poly(styrene-butyl acrylate-acrylononitril- e-acrylic acid); a
process wherein the colorant is carbon black, cyan, yellow,
magenta, or mixtures thereof, and the toner isolated is from about
2 to about 25 microns in volume average diameter, and the particle
size distribution thereof is optionally from about 1.15 to about
1.30, and wherein there is optionally added to the surface of the
formed toner metal salts, metal salts of fatty acids, silicas,
metal oxides, or mixtures thereof, each in an amount, for example,
of from about 0.1 to about 10 percent by weight of the obtained
toner; a process wherein the colorant is a colorant dispersion
comprised of
[0028] (i) colorant, water, an ionic surfactant, a nonionic
surfactant or mixtures of an ionic surfactant, and a nonionic
surfactant; the latex is a latex emulsion; and wherein the
[0029] (ii) colorant dispersion is blended with the latex emulsion
comprised of resin, a nonionic surfactant and an ionic surfactant,
and optionally adding a wax dispersion comprised, for example, of
submicron wax particles in the diameter of from about 0.1 to about
0.4 micron dispersed in an ionic surfactant of the same charge
polarity as that of the ionic surfactant in the colorant dispersion
or latex emulsion;
[0030] (iii) heating the resulting mixture below about, or about
equal to the glass transition temperature (Tg) of the latex resin
to form toner sized aggregates;
[0031] (iv) heating the resulting aggregate suspension above about
the Tg of the latex resin; adding a methacrylate copolymer,
available from Rohm American Inc. as EUDRAGIT.TM., and isolating
the toner, which toner contains the methacrylate copolymer on the
surface thereof; a process for the preparation of toner
comprising
[0032] (i) providing or generating a latex emulsion of resin,
water, and an ionic surfactant, and providing or generating a
colorant dispersion containing a colorant, water, an ionic
surfactant, or a nonionic surfactant;
[0033] (ii) optionally providing or generating a wax dispersion
containing an anionic surfactant similarly charged to that of the
latex surfactant emulsion;
[0034] (iii) blending (ii) with the colorant dispersion; (iv)
heating the resulting mixture below the glass transition
temperature (Tg) of the latex resin;
[0035] (v) heating (vii) above about the Tg of the latex resin;
[0036] (vi) followed by the addition of a methacrylate copolymer,
available from Rohm American Inc. as EUDRAGIT.TM., in an amount of
from about 3 to about 7 percent by weight;
[0037] (vii) retaining the mixture (vi) at a temperature of from
about 70.degree. C. to about 95.degree. C. for about 3 to about 10
hours;
[0038] (viii) washing the resulting toner slurry; and
[0039] (ix) isolating the toner; a process wherein the added latex
contains the same resin as the initial latex of (i), or wherein the
added latex contains a dissimilar resin than that of the initial
latex resin (i); a process wherein aggregation of latex resin and
colorant is accomplished by heating at a temperature below the
glass transition temperature of the resin or polymer contained in
the latex, and coalescence is accomplished by heating at a
temperature of above the glass transition temperature of the
polymer contained in the latex (i) to enable fusion or coalescence
of colorant and latex resin, followed by the mixing of the
composition resulting with a methacrylate copolymer; a process
wherein the aggregation temperature is from about 45.degree. C. to
about 55.degree. C., and the coalescence temperature is from about
75.degree. C. to about 95.degree. C.; a process wherein the latex
emulsion comprises submicron resin particles of a diameter of about
100 to about 500 nanometers, and more specifically, in the size
range of about 150 to about 400 nanometers in water and an ionic
surfactant, and more specifically, an anionic surfactant; the
colorant dispersion comprises submicron pigment particles of about
50 to about 250 nanometers, and more specifically, of about 80 to
about 200 nanometers in size diameter; a toner process wherein the
cationic surfactant comprises, for example, dialkyl benzenealkyl
ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl
methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide,
benzalkonium chloride, cetyl pyridinium bromide, C.sub.12,
C.sub.15, C.sub.17 trimethyl ammonium bromides, halide salts of
quaternized polyoxyethylalkylamines, dodecylbenzyl triethyl
ammonium chloride, and which coagulant surfactant component is
selected in an amount of, for example, from about 0.01 to about 10
percent by weight of toner; a process wherein there is added during
or subsequent to (v) a second latex, and which latex is comprised
of submicron resin particles suspended in an aqueous phase
containing an ionic surfactant, and wherein the second latex is
optionally selected in an amount of about 15 to about 35 percent by
weight of the initial latex; a process wherein the second latex
(vi) is added and enables formation of a coating on the resulting
toner aggregates of (v), and wherein the thickness of the formed
coating is from about 0.1 to about 1 micron; a process wherein the
aggregation temperature is from about 50.degree. C. to about
60.degree. C., and the coalescence temperature is from about
80.degree. C. to about 95.degree. C.; a process wherein the latex
(i) or added latex contains a resin selected from the group
consisting of a number of suitable know resins, or polymers, and
more specifically poly(styrene-butadiene),
poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene),
poly(ethyl methacrylate-butadiene), poly(propyl
methacrylate-butadiene), poly(butyl methacrylate-butadiene),
poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene),
poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene),
poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl
methacrylate-isoprene), poly(ethyl methacrylate-isoprene),
poly(propyl methacrylate-isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl
acrylate-isoprene), poly(propyl acrylate-isoprene), poly(butyl
acrylate-isoprene), poly(styrene-propyl acrylate),
poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid),
poly(styrene-butadiene-m- ethacrylic acid),
poly(styrene-butadiene-acrylonitrile-acrylic acid),
poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl
acrylate-methacrylic acid), poly(styrene-butyl
acrylate-acrylononitrile), and poly(styrene-butyl
acrylate-acrylononitrile-acrylic acid); a process wherein the toner
colorant is carbon black, cyan, yellow, magenta, or mixtures
thereof, and the toner isolated is from about 1 to about 25 microns
in volume average diameter, and the particle size distribution
thereof is optionally from about 1.15 to about 1.30; and wherein
there is added to the surface of the formed toner metal salts,
metal salts of fatty acids, silicas, metal oxides, or mixtures
thereof, each in an amount of from about 0.1 to about 3 percent by
weight of the obtained toner.
[0040] Examples of polyester resins are as indicated herein and in
the appropriate U.S. patents recited herein, and more specifically,
examples of a number of polyesters that can be selected are
copoly(1,2-propylene-dipropylene-5-sulfoisophthalate)-copoly(1,2-propylen-
e-dipropylene terephthalate),
copoly(1,2-propylene-diethylene-5-sulfoisoph-
thalate)-copoly(1,2-propylene-diethylene terephthalate),
copoly(propylene-5-sulfoisophthalate)-copoly(1,2-propylene
terephthalate),
copoly(1,3-butylene-5-sulfoisophthalate)-copoly(1,3-butyl- ene
terephthalate),
copoly(butylenesulfoisophthalate)-copoly(1,3-butylene
terephthalate), and the like.
[0041] The methacrylate copolymers, available from Rohm American
Inc. as, for example, EUDRAGIT.TM., and more specifically,
butylmethacrylate-(2-di-
methylaminoethyl)methacrylate-methylmethacrylate copolymer (1:2:1),
can be dispersed in water. The copolymer possesses an average
particle size diameter of, for example, from about 50 to about 500
nanometers, and more specifically, from about 100 to about 300
nanometers. Examples of specific polymers that may be selected are
EUDRAGIT.TM. RL and RS (Rohm Pharma) which are copolymers believed
synthesized from acrylic and methacrylic esters with quaternary
ammonium groups. EUDRAGIT.TM. RL and RS differ in the molar ratios
of the ammonium groups to the remaining neutral (meth)acrylic acid
esters, about 1:20 and about 1:40, respectively. EUDRAGIT.TM. NE is
an aqueous dispersion of a neutral copolymer based on ethyl
acrylate and methyl methacrylate. EUDRAGIT.TM. RD 100 is the powder
form of copolymers of acrylates and methacrylates with a
quarternary ammonium group in combination with sodium
carboxymethylcellulose.
[0042] More specifically, of value with the processes of the
present invention is the use of a particular cationic polymer,
EEPO, which is reversibly soluble-insoluble in an aqueous solution
when the pH is changed, therefore, the solubility of EEPO can be
considered pH dependent. The EEPO becomes water soluble via salt
formation with acids and can be added in this form to the acidic
toner slurry. It is hypothesized that the water soluble polymer
would interact in solution with the toner particles even at low pH.
Once the polymer has time to adsorb on the toner particles, the pH
can be shifted to basic conditions. At this point the polymer will
precipitate onto the toner's surface and form a film around the
toner upon the evaporation of water. The surface of the toner is
hypothesized to acquire the cationic characteristics of the polymer
resulting in a positively charged toner. More specifically, in
embodiments the EEPO polymer contains tertiary amino functional
groups capable of ionic interactions with, for example, sulfonated
groups on the surface of the polyester toner. The neighboring
polymer chain and toner particle surface become complexed to one
another resulting in a modification of the properties of the
particle surface and thus the tribocharging characteristics. The
surface treatment approach in embodiments is to add the polymer in
its dissolved form to the toner slurry following the toner
fabrication process. The toner slurry is adjusted to pH of, for
example, from about 2 to about 3 to permit the EEPO to remain
dissolved during the addition period. Also, it is hypothesized that
the water-soluble polymer interacts with the toner particles via
electrostatic attraction, even at low pH, and will not
substantially precipitate or irreversibly complex to each other.
Once the pH is increased to from about 10 to about 12, the EEPO
will precipitate onto the toner surface and form a film or layer of
positive-charged polymeric material around the toner surface.
Evaporating the water from the toner by, for example, freeze drying
the toner particles promotes further coalescence of the polymeric
film to the toner surface.
[0043] Various known colorants, especially pigments, present in the
toner in an effective amount of, for example, from about 1 to about
65, and more specifically, from about 2 to about 35 percent by
weight of the toner, and more specifically, in an amount of from
about 1 to about 15 percent by weight, and wherein the total of all
toner components is about 100 percent, include carbon black like
REGAL 330.RTM.; magnetites such as Mobay magnetites MO8029.TM.,
MO8060.TM.; and the like. As colored pigments, there can be
selected known cyan, magenta, yellow, red, green, brown, blue or
mixtures thereof. Specific examples of colorants, especially
pigments, include phthalocyanine HELIOGEN BLUE L6900.TM.,
D6840.TM., D7080.TM., D7020.TM., Cyan 15:3, Magenta Red 81:3,
Yellow 17, the pigments of U.S. Pat. No. 5,556,727, the disclosure
of which is totally incorporated herein by reference, and the like.
Examples of specific magentas that may be selected include, for
example, 2,9-dimethyl-substituted quinacridone and anthraquinone
dye identified in the Color Index as CI 60710, CI Dispersed Red 15,
diazo dye identified in the Color Index as CI 26050, CI Solvent Red
19, and the like. Illustrative examples of specific cyans that may
be selected include copper tetra(octadecyl sulfonamido)
phthalocyanine, x-copper phthalocyanine pigment listed in the Color
Index as CI 74160, CI Pigment Blue, and Anthrathrene Blue,
identified in the Color Index as CI 69810, Special Blue X-2137, and
the like; while illustrative specific examples of yellows that may
be selected are Diarylide Yellow 3,3-dichlorobenzidene
acetoacetanilides, a monoazo pigment identified in the Color Index
as CI 12700, CI Solvent Yellow 16, a nitrophenyl amine sulfonamide
identified in the Color Index as Foron Yellow SE/GLN, Cl Dispersed
Yellow 33 2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2,5-
-dimethoxy acetoacetanilide, and Permanent Yellow FGL. Colored
magnetites, such as mixtures of MAPICO BLACK.TM., and cyan
components, may also be selected as pigments with the process of
the present invention. The colorants, such as pigments, selected
can be flushed pigments as indicated herein.
[0044] More specifically, colorant examples include Pigment Blue
15:3 having a Color Index Constitution Number of 74160, Magenta
Pigment Red 81:3 having a Color Index Constitution Number of
45160:3, Yellow 17 having a Color Index Constitution Number of
21105, and known dyes such as food dyes, yellow, blue, green, red,
magenta dyes, and the like. Colorants include pigments, dyes,
mixtures of pigments, mixtures of dyes, mixtures of dyes and
pigments, and the like, and preferably pigments.
[0045] Dry powder additives that can be added or blended onto the
surface of the toner compositions preferably after washing or
drying include, for example, metal salts, metal salts of fatty
acids, colloidal silicas, metal oxides like titanium, tin and the
like, mixtures thereof and the like, which additives are each
usually present in an amount of from about 0.1 to about 2 weight
percent, reference U.S. Pat. Nos. 3,590,000; 3,720,617; 3,655,374
and 3,983,045, the disclosures of which are totally incorporated
herein by reference. Preferred additives include zinc stearate and
flow aids, such as fumed silicas like AEROSIL R972.RTM. available
from Degussa, or silicas available from Cabot Corporation or
Degussa Chemicals, the coated silicas of U.S. Pat. No. 6,004,714
and U.S. Pat. No. 6,190,815, the disclosures of which are totally
incorporated herein by reference, and the like, each in amounts of
from about 0.1 to about 2 percent, which can be added during the
aggregation process or blended into the formed toner product.
[0046] Developer compositions can be prepared by mixing the toners
with known carrier particles, including coated carriers, such as
steel, ferrites, and the like, reference U.S. Pat. Nos. 4,937,166
and 4,935,326, the disclosures of which are totally incorporated
herein by reference, for example from about 2 percent toner
concentration to about 8 percent toner concentration.
[0047] Imaging methods are also envisioned with the toners of the
present invention, reference for example a number of the patents
mentioned herein, and U.S. Pat. No. 4,265,990, the disclosure of
which is totally incorporated herein by reference.
[0048] With further respect to the present invention, in
embodiments thereof illustrative examples of resin, polymer or
polymers selected for the process of the present invention and
present in the latex (i) or added latex include known polymers as
illustrated herein, such as acrylates, methacrylates, polyesters
like poly(styrene-butadiene), poly(methyl methacrylate-butadiene),
poly(ethyl methacrylate-butadiene), poly(propyl
methacrylate-butadiene), poly(butyl methacrylate-butadiene),
poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene),
poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene),
poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl
methacrylate-isoprene), poly(ethyl methacrylate-isoprene),
poly(propyl methacrylate-isoprene), poly(butyl
methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl
acrylate-isoprene), poly(propyl acrylate-isoprene), poly(butyl
acrylate-isoprene), poly(styrene-butylacrylate),
poly(styrene-butadiene), poly(styrene-isoprene), poly(styrene-butyl
methacrylate), poly(styrene-butyl acrylate-acrylic acid),
poly(styrene-butadiene-acrylic acid), poly(styrene-isoprene-acrylic
acid), poly(styrene-butyl methacrylate-acrylic acid), poly(butyl
methacrylate-butyl acrylate), poly(butyl methacrylate-acrylic
acid), poly(styrene-butyl acrylate-acrylonitrile-acrylic acid),
poly(acrylonitrile-butyl acrylate-acrylic acid), and the like; the
latex polymer, or resin is generally present in the toner
compositions in various suitable amounts, such as from about 75 to
about 98 percent by weight, or from about 80 to about 95 percent by
weight of the toner or of the solids, and the latex size suitable
for the processes of the present invention can be, for example,
from about 0.05 micron to about 0.5 micron in volume average
diameter as measured by the Brookhaven nanosize particle analyzer.
Other sizes and effective amounts of latex polymer may be selected
in embodiments. The total of all toner components, such as resin,
calcium stearate, and colorant, is about 100 percent, or about 100
parts.
[0049] The polymer selected for the process of the present
invention can be prepared by emulsion polymerization methods, and
the monomers utilized in such processes include, for example,
styrene, acrylates, methacrylates, butadiene, isoprene, acrylic
acid, methacrylic acid, itaconic acid, beta carboxy ethyl acrylate,
acrylonitrile, and the like. Known chain transfer agents, for
example dodecanethiol, from, for example, about 0.1 to about 10
percent, or carbon tetrabromide in effective amounts, such as for
example from about 0.1 to about 10 percent, can also be utilized to
control the molecular weight properties of the polymer when
emulsion polymerization is selected. Other processes of obtaining
polymer particles of from, for example, about 0.01 micron to about
2 microns can be selected from polymer microsuspension process,
such as disclosed in U.S. Pat. No. 3,674,736, the disclosure of
which is totally incorporated herein by reference; polymer solution
microsuspension process, such as disclosed in U.S. Pat. No.
5,290,654, the disclosure of which is totally incorporated herein
by reference, mechanical grinding processes, or other known
processes.
[0050] Examples of optional waxes include those as illustrated
herein, polypropylenes and polyethylenes commercially available
from Allied Chemical and Petrolite Corporation, wax emulsions
available from Michaelman Inc. and the Daniels Products Company,
EPOLENE N-15.TM. commercially available from Eastman Chemical
Products, Inc., VISCOL 550-P.TM., a low weight average molecular
weight polypropylene available from Sanyo Kasei K.K., and similar
materials. The commercially available polyethylenes selected
possess, it is believed, a molecular weight Mw of from about 1,000
to about 1,500, while the commercially available polypropylenes
utilized for the toner compositions of the present invention are
believed to have a molecular weight of from about 4,000 to about
5,000. Examples of functionalized waxes include amines, amides, for
example AQUA SUPERSLIP 6550.TM., SUPERSLIP 6530.TM. available from
Micro Powder Inc., fluorinated waxes, for example POLYFLUO 190.TM.,
POLYFLUO 200.TM., POLYFLUO 523XF.TM., AQUA POLYFLUO 411.TM., AQUA
POLYSILK 19.TM., POLYSILK 14.TM. available from Micro Powder Inc.,
mixed fluorinated, amide waxes, for example MICROSPERSION 19.TM.
also available from Micro Powder Inc., imides, esters, quaternary
amines, carboxylic acids or acrylic polymer emulsion, for example
JONCRYL 74.TM., 89.TM., 130.TM., 537.TM., and 538.TM., all
available from SC Johnson Wax, chlorinated polypropylenes and
polyethylenes available from Allied Chemical and Petrolite
Corporation and SC Johnson wax.
[0051] Examples of initiators for the latex preparation include
water soluble initiators, such as ammonium and potassium
persulfates, in suitable amounts, such as from about 0.1 to about 8
percent, and more specifically, from about 0.2 to about 5 percent
(percent by weight). Examples of organic soluble initiators include
Vazo peroxides, such as VAZO 64.TM., 2-methyl 2-2'-azobis
propanenitrile, and VAZO 88.TM., 2-2'-azobis isobutyramide
dehydrate in a suitable amount, such as in the range of from about
0.1 to about 8 percent. Examples of chain transfer agents include
dodecanethiol, octanethiol, carbon tetrabromide, and the like in
various suitable amounts, such as in an amount of from about 0.1 to
about 10 percent, and more specifically, from about 0.2 to about 5
percent by weight of monomer.
[0052] Surfactants for the preparation of latexes and colorant
dispersions can be ionic or nonionic surfactants in effective
amounts of, for example, from about 0.01 to about 15, or from about
0.01 to about 5 percent by weight of the reaction mixture. Anionic
surfactants include sodium dodecylsulfate (SDS), sodium
dodecylbenzene sulfonate, sodium dodecylnaphthalene sulfate,
dialkyl benzenealkyl, sulfates and sulfonates, abitic acid,
available from Aldrich, NEOGEN R.TM., NEOGEN SC.TM. obtained from
Kao, and the like. Examples of cationic surfactants are dialkyl
benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride,
alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl
ammonium bromide, benzalkonium chloride, cetyl pyridinium bromide,
C.sub.12, C.sub.15, C.sub.17 trimethyl ammonium bromides, halide
salts of quaternized polyoxyethylalkylamines, dodecylbenzyl
triethyl ammonium chloride, MIRAPOL.TM. and ALKAQUAT.TM. available
from Alkaril Chemical Company, SANIZOL.TM. (benzalkonium chloride)
available from Kao Chemicals, and the like, selected in effective
amounts of, for example, from about 0.01 percent to about 10
percent by weight. The molar ratio of the cationic surfactant used
for flocculation to the anionic surfactant used in the latex
preparation is, for example, from about 0.5 to about 4.
[0053] Examples of nonionic surfactants selected in various
suitable amounts, such as about 0.1 to about 5 percent by weight,
are polyvinyl alcohol, polyacrylic acid, methalose, methyl
cellulose, ethyl cellulose, propyl cellulose, hydroxy ethyl
cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether,
polyoxyethylene lauryl ether, polyoxyethylene octyl ether,
polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether,
polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl
ether, polyoxyethylene nonylphenyl ether, dialkylphenoxy
poly(ethyleneoxy) ethanol, available from Rhone-Poulenac as IGEPAL
CA-210.TM., IGEPAL CA-520.TM., IGEPAL CA-720.TM., IGEPAL
CO-890.TM., IGEPAL CO-720.TM., IGEPAL CO-290.TM., IGEPAL
CA-210.TM., ANTAROX 890.TM. and ANTAROX 897.TM., can be
selected.
[0054] The following Examples are presented.
Preparation of Sodio Sulfonated Polyesters
[0055] A linear sulfonated random copolyester resin comprised of,
on a mol percent, 0.465 of terephthalate, 0.035 of sodium
sulfoisophthalate, 0.475 of 1,2-propanediol, and 0.025 of
diethylene glycol was prepared as follows. In a 5 gallon Parr
reactor equipped with a bottom drain valve, double turbine
agitator, and distillation receiver with a cold water condenser
were charged 3.98 kilograms of dimethylterephthalate, 451 grams of
sodium dimethyl sulfoisophthalate, 3.104 kilograms of
1,2-propanediol (1 mole excess of glycol), 351 grams of diethylene
glycol (1 mole excess of glycol), and 8 grams of butyltin hydroxide
oxide catalyst. The reactor was then heated to 165.degree. C. with
stirring for 3 hours whereby 1.33 kilograms of distillate were
collected in the distillation receiver, and which distillate was
comprised of about 98 percent by volume of methanol and 2 percent
by volume of 1,2-propanediol as measured by the ABBE refractometer
available from American Optical Corporation. The reactor mixture
was then heated to 190.degree. C. over a one hour period, after
which the pressure was slowly reduced from atmospheric pressure to
about 260 Torr over a one hour period, and then reduced to 5 Torr
over a two hour period with the collection of approximately 470
grams of distillate in the distillation receiver, and which
distillate was comprised of approximately 97 percent by volume of
1,2-propanediol and 3 percent by volume of methanol as measured by
the ABBE refractometer. The pressure was then further reduced to
about 1 Torr over a 30 minute period whereby an additional 530
grams of 1,2-propanediol were collected. The reactor was then
purged with nitrogen to atmospheric pressure, and the polymer
product discharged through the bottom drain onto a container cooled
with dry ice to yield 5.60 kilograms of 3.5 mol percent sulfonated
polyester resin, sodio salt of
(1,2-propylene-dipropylene-5-sulfoisophthalate)-copo-
ly(1,2-propylene-dipropylene terephthalate). The sulfonated
polyester resin glass transition temperature was measured to be
56.6.degree. C. (onset) utilizing the 910 Differential Scanning
Calorimeter available from E.I. DuPont operating at a heating rate
of 10.degree. C. per minute. The number average molecular weight
was measured to be 3,250 grams per mole, and the weight average
molecular weight was measured to be 5,290 grams per mole using
tetrahydrofuran as the solvent.
Preparation of a Sodio Sulfonated Polyester Colloid Solution
[0056] A 15 percent solids concentration of a colloidal solution of
the above prepared sodio-sulfonated polyester resin particles with
particle diameter sizes of from about 5 to about 150 nanometers,
and typically about 20 to about 40 nanometers dissipated in 85
percent aqueous media of water was prepared by first heating about
2 liters of deionized water to about 85.degree. C. with stirring,
and adding thereto 300 grams of the above prepared sulfonated
polyester resin, followed by continued heating at about 85.degree.
C., and stirring of the mixture for a duration of from about one to
about two hours, followed by cooling to about room temperature,
about 25.degree. C. throughout the Examples. The resulting
colloidal solution of sodio-sulfonated polyester resin particles
possessed a characteristic blue tinge and particle sizes of from
about 5 to about 150 nanometers, and typically of about 20 to about
40 nanometers, as measured by the NiCOMPO particle sizer.
COMPARATIVE EXAMPLE 1
[0057] (VF173/Control):
[0058] A pilot plant batch of toner PP-5695-EAP-4-C34W comprised of
the sodio-sulfonated polyester SPE4, 12 percent solids and 88
percent deionized water, 9 percent carnauba wax dispersion and 6
percent by weight of FLEXIVERSE BLUE.TM. (Pigment Blue 15:3,
BFD1121, 47.1 percent solids) dispersion (Sun Chemical Company) was
prepared. Aggregation of the cyan polyester toner particles was
completed at 58.degree. C. (degrees Centigrade throughout) in a 30
gallon stainless steel reactor (of which only 20 kilograms of the
toner yield were used for bench scale studies). The agitation rate
was set initially to 100 RPM. A 5 percent zinc acetate solution was
added as the coagulant by fast initial zinc addition (FIZA)
technique as illustrated in U.S. Pat. No. 6,395,445, the disclosure
of which is totally incorporated herein by reference, where 60 to
80 percent of the total zinc acetate solution was added quickly
(600 grams/minute for the first 30 minutes) and the remainder (80
to 100 grams/minute thereafter) was added at a reduced rate. The
amount of zinc acetate added equaled approximately 11 percent of
the total resin in the emulsion. After 7 hours of aggregation, the
particle size reached 5.24 .mu.m with a GSD of 1.2. Full cooling
was applied and particles were sieved at about 30.degree. C. to
about 35.degree. C. through a 25 .mu.m nylon filter bag. A portion
of the toner slurry was washed in the lab three times with
deionized water after the mother liquor removal, resuspended to
approximately 25 percent weight solids and freeze dried for 48
hours to provide the untreated parent toner (VF173 or Control).
This toner was comprised of 85 percent sodio-sulfonated polyester,
9 percent carnauba wax dispersion and 6 percent by weight of
FLEXIVERSE BLUE.TM. pigment.
COMPARATIVE EXAMPLE 2
[0059] (JC003G/Control):
[0060] A pilot plant batch of toner PP-5738-EAP-4-C37 comprised of
a sodio-sulfonated polyester (SPE4, 12 percent solids and 88
percent deionized water) and 6 percent by weight of FLEXIVERSE
BLUE.TM. (Pigment Blue 15:3, BFD1121, 47.1 percent solids)
dispersion (Sun Chemical Company) was prepared. Aggregation of the
cyan polyester particles was completed at 58.degree. C. (degrees
Centigrade throughout) in, a 5 gallon stainless steel reactor. The
agitation rate was set to 150 RPM. A 3 percent zinc acetate
solution was added as the coagulant via FIZA or fast initial zinc
addition technique as illustrated in U.S. Pat. No. 6,395,445, the
disclosure of which is totally incorporated herein by reference,
where 60 to 80 percent of the total zinc acetate solution was added
quickly (600 grams/minute for the first 30 minutes) and the
remainder (80 to 100 grams/minute thereafter) was added at a
reduced rate. The amount of zinc acetate added equaled
approximately 12 percent of the total resin in the emulsion. After
8 hours of aggregation, the particle size reached 5.95 .mu.m with a
GSD of 1.16. Full cooling was applied and particles were sieved at
about 30.degree. C. to about 35.degree. C. through a 25 .mu.m nylon
filter bag. A portion of the resulting toner slurry was washed in
the lab three times with deionized water after the mother liquor
removal, resuspended to approximately 25 percent weight solids and
freeze dried for 48 hours to provide the untreated parent toner
(JC003G or Control). This toner was comprised of 94 percent
sodio-sulfonated polyester and 6 percent by weight of FLEXIVERSE
BLUE.TM. pigment.
EXAMPLE I
[0061] (VF246):
[0062] Preparation of EEPO Solution:
[0063] An aminoalkylmethacrylate copolymer EUDRAGIT.TM. EPO (EEPO),
which was delivered as a 1 percent (wt/wt) solution in deionized
water (DIW), was prepared by dissolving 1.26 grams of the EEPO in
124.7 grams of 0.3 M HNO.sub.3; the pH of the solution was lowered
to 2 by adding 2.4 grams of 1 M HNO.sub.3. Lowering the pH of the
aqueous solution to 2 ensured complete solubility of the EEPO
polymer in the solution. The final total percentage of EEPO to
toner was about 3 percent weight of dry toner.
[0064] Coating Procedure of EEPO onto Surface of Polyester Toner
Particles:
[0065] The stock pilot plant toner of 85 percent sodio-sulfonated
polyester, 9 percent carnauba wax dispersion and 6 percent by
weight of FLEXIVERSE BLUE.TM. pigment (PP-5695-EAP-4-C34W) was
treated in the lab via a pH shifting procedure where EEPO is
soluble or insoluble in an aqueous solution depending on the pH of
the aqueous solution.
[0066] A 327 gram quantity of the toner slurry (12.9 percent by
weight solids in 87.1 percent mother liquor) comprised of 85
percent of the sodio-sulfonated polyester, 9 percent carnauba wax
dispersion and 6 percent by weight of FLEXIVERSE BLUE.TM. pigment
was separated from its mother liquor via decanting, and then
stirred in a 1 liter glass Erlenmeyer flask on a stir plate at
about 250 to about 300 rpm. The pH of the toner slurry was lowered
from about 5.5 to about 2.4 by the addition of 70 grams of 0.3 M
HNO.sub.3. The EEPO solution was added dropwise to the toner slurry
and stirred for 1 hour at room temperature. After 1 hour, the pH of
the toner slurry was increased to 12.2 with 71 grams of 1 M NaOH
and left to stir at 300 rpm for 18 to 20 hours overnight at ambient
temperature. The surface treated toner was then filtered and washed
four times. The filtercake was then resuspended to approximately 25
percent by weight solids and freeze dried. The pH of the filtrates
were always greater than 9.5 and showed no sign of precipitated
EEPO; it can be assumed that all EEPO polymer was transferred to
the toner surface. This toner was comprised of 85 percent
sodio-sulfonated polyester, 9 percent carnauba wax dispersion and 6
percent by weight of FLEXIVERSE BLUE.TM. pigment with 3 percent
EEPO relative to dry toner weight deposited or coated on the
toner's surface.
EXAMPLE II
[0067] (JC003B-2):
[0068] Preparation of EEPO Solution:
[0069] An aminoalkylmethacrylate copolymer of EUDRAGIT.TM. EPO
(EEPO), which was delivered as a 1.9 percent (wt/wt) solution in
deionized water (DIW), was prepared by dissolving 0.862 gram of the
EEPO in 43.10 grams of acidified water (pH=1.42 with nitric acid);
the pH of the solution was lowered to 2.12 by adding 2.41 grams of
1 M HNO.sub.3. Lowering the pH of the aqueous solution to 2.12
ensured complete solubility of the EEPO polymer in the solution.
The total percentage of EEPO to toner was to equal 1 percent weight
of dry toner.
[0070] Coating Procedure of EEPO onto Surface of Polyester Toner
Particles:
[0071] The stock pilot plant toner of 94 percent of the
sodio-sulfonated polyester and 6 percent by weight of FLEXIVERSE
BLUE.TM. pigment (PP-5738-EAP-4-C37) was treated in the lab via a
pH shifting procedure where EEPO was soluble or insoluble in an
aqueous solution depending on the pH of the aqueous solution.
[0072] A 570.1 gram quantity of the toner slurry (15.1
percent-weight solids in 84.9 percent mother liquor) of 94 percent
sodio-sulfonated polyester and 6 percent by weight of FLEXIVERSE
BLUE.TM. pigment was separated from its mother liquor via
decanting, and then stirred in a 1 liter glass Erlenmeyer flask on
a stir plate at 450 rpm. The pH of the toner slurry was lowered
from about 5.48 to about 2.49 by the addition of 65.2 grams of 0.5
M HNO.sub.3. The EEPO solution was added via a low flow VWR
peristaltic pump at a rate of 1.08 grams per minute (or a total
time of 42 minutes) to the toner slurry at room temperature. The
toner was then stirred for an hour at room temperature after the
addition of EEPO. After the one hour of stirring, the pH of the
toner slurry was increased to 11.28 with 64.23 grams of 1 M NaOH
and left to stir at 450 rpm for another hour. The toner was then
left to sit overnight at ambient temperature. Thereafter, the
surface treated toner was then filtered and washed two times. The
filtercake was then resuspended to approximately 25 percent by
weight solids and freeze dried. The pH of the filtrates were
usually greater than 7.5 and evidenced no sign of precipitated
EEPO; it can thus be assumed that all EEPO polymer was transferred
to the toner surface. The resulting toner was comprised of 94
percent of the above sodio-sulfonated polyester and 6 percent by
weight of FLEXIVERSE BLUE.TM. pigment with 1 percent EEPO relative
to the dry toner weight deposited or coated on the toner
surface.
EXAMPLE III
[0073] (JC003C-2):
[0074] Preparation of EEPO Solution:
[0075] An aminoalkylmethacrylate copolymer of EUDRAGIT.TM. EPO
(EEPO), which was delivered as a 1.9 percent (wt/wt) solution in
deionized water (DIW), was prepared by dissolving 2.59 grams of the
EEPO in 129.50 grams of acidified water (pH=1.42 with nitric acid);
the pH of the solution was lowered to 2.23 by adding 4.61 grams of
1 M HNO.sub.3. Lowering the pH of the aqueous solution to 2.2
ensured complete solubility of the EEPO polymer in the solution.
The total percentage of EEPO to toner was to equal 3 percent weight
of dry toner.
[0076] Coating Procedure of EEPO onto Surface of Polyester Toner
Particles:
[0077] The stock pilot plant toner of 94 percent sodio-sulfonated
polyester and 6 percent by weight of FLEXIVERSE BLUE.TM. pigment
(PP-5738-EAP-4-C37) was treated in the lab via a pH shifting
procedure where EEPO was soluble or insoluble in an aqueous
solution depending on the pH of the aqueous solution.
[0078] A 570.9 gram quantity of the toner slurry (15.1 percent by
weight solids in 84.9 percent mother liquor) of 94 percent of the
above sodio sulfonated polyester and 6 percent by weight of
FLEXIVERSE BLUE.TM. pigment was separated from its mother liquor
via decanting, and then stirred in a 1 liter glass Erlenmeyer flask
on a stir plate at 450 rpm. The pH of the toner slurry was lowered
from about 5.54 to about 2.42 by the addition of 67.6 grams of 0.5
M HNO.sub.3. The EEPO solution was added via a low flow VWR
peristaltic pump at a rate of 1.38 grams per minute (or a total
time of 97 minutes) to the toner slurry at room temperature. The
toner was then stirred for an extra hour at room temperature after
the addition of EEPO. Subsequent to one hour of stirring, the pH of
the toner slurry was increased to 11.26 with 68.45 grams of 1 M
NaOH and left to stir at 450 rpm for another hour. The toner was
then retained overnight at ambient temperature, then the surface
treated toner was filtered and washed three times. The filtercake
resulting was then resuspended to approximately 25 percent by
weight solids and freeze dried. The pH of the filtrates were
greater than 7.5 and showed no sign of precipitated EEPO; it is
believed that all EEPO polymer was transferred to the toner
surface. The resulting toner was comprised of 94 percent of the
sodio-sulfonated polyester and 6 percent by weight of FLEXIVERSE
BLUE.TM. pigment with 3 percent EEPO relative to dry toner weight
deposited or coated on the toner's surface.
EXAMPLE IV
[0079] (JC003E):
[0080] Preparation of EEPO Solution:
[0081] An aminoalkylmethacrylate copolymer of EUDRAGIT.TM. EPO
(EEPO), which was delivered as a 1.9 percent (wt/wt) solution in
deionized water (DIW), was prepared by dissolving 3.682 grams of
the EEPO in 184.10 grams of acidified water (pH=1.42 with nitric
acid); and the pH of the solution was lowered to 2.25 by adding
9.31 grams of 1 M HNO.sub.3. Lowering the pH of the aqueous
solution to 2.2 ensured complete solubility of the EEPO polymer in
the solution. The total percentage of EEPO to toner was to equal 7
percent weight of dry toner.
[0082] Coating Procedure of EEPO onto Surface of Polyester Toner
Particles:
[0083] The stock pilot plant toner of 94 percent sodio-sulfonated
polyester and 6 percent by weight of FLEXIVERSE BLUE.TM. pigment
(PP-5738-EAP-4-C37) was treated in the lab via a pH shifting
procedure where EEPO was soluble or insoluble in an aqueous
solution depending on the pH of the aqueous solution.
[0084] A 522.46 gram quantity of the toner slurry (10.1 percent by
weight solids in 89.9 percent mother liquor) of 94 percent of the
above sodio-sulfonated polyester and 6 percent by weight of
FLEXIVERSE BLUE.TM. pigment was separated from its mother liquor
via decanting, and then stirred in a 1 liter glass Erlenmeyer flask
on a stir plate at 450 rpm. The pH of the toner slurry was lowered
from about 5.62 to about 2.45 by the addition of 72.7 grams of 0.5
M HNO.sub.3. The EEPO solution was added via a low flow VWR
peristaltic pump at a rate of 1.19 grams per minute (or a total
time of 162 minutes) to the toner slurry at room temperature. The
toner was then stirred for an extra hour at room temperature after
the addition of EEPO. Subsequent to one hour of stirring, the pH of
the toner slurry was increased to 11.27 with 97.2 grams of 1 M NaOH
and left to stir at 450 rpm for another hour. The toner was
retained overnight at ambient temperature; then the surface-treated
toner was filtered and washed two times. The filtercake resulting
was then resuspended to approximately 25 percent by weight solids
and freeze-dried. The pH of the filtrates was greater than 7.9 and
showed no sign of precipitated EEPO; it is believed that all EEPO
polymer was transferred to the toner surface. The resulting toner
was comprised of 94 percent of the sodio-sulfonated polyester and 6
percent by weight of FLEXIVERSE BLUE.TM. pigment with 7 percent
EEPO relative to dry toner weight deposited or coated on the
toner's surface.
EXAMPLE V
[0085] (JC026A):
[0086] Preparation of EEPO Solution:
[0087] An aminoalkylmethacrylate copolymer of EUDRAGIT.TM. EPO
(EEPO), which was delivered as a 1.9 percent (wt/wt) solution in
deionized water (DIW), was prepared by dissolving 2.67 grams of the
EEPO in 133.47 grams of acidified water (pH=1.43 with nitric acid);
the pH of the solution was lowered to 2.05 by adding 5.32 grams of
1 M HNO.sub.3. Lowering the pH of the aqueous solution to 2 ensured
complete solubility of the EEPO polymer in the solution. The total
percentage of EEPO to toner was to equal 5 percent by weight of dry
toner.
[0088] Coating Procedure of EEPO onto Surface of Polyester Toner
Particles:
[0089] The stock pilot plant toner of 85 percent sodio-sulfonated
polyester, 9 percent carnauba wax dispersion and 6 percent by
weight of black REGAL 330.RTM., FLEXIVERSE.TM. pigment
(PP-6073-EAP-R5-K6W) was treated in the lab via a pH shifting
procedure where EEPO is soluble or insoluble in an aqueous solution
depending on the pH of the aqueous solution.
[0090] A 325.15 gram quantity of the toner slurry (16.4 percent by
weight solids in 83.6 percent mother liquor) of 85 percent of the
above sodio-sulfonated polyester, 9 percent carnauba wax dispersion
and 6 percent by weight of black REGAL 330.RTM., FLEXIVERSE.TM.
pigment was separated from its mother liquor via decanting, and
then stirred in a 1 liter glass Erlenmeyer flask on a stir plate at
450 rpm. The pH of the toner slurry was lowered from about 5.62 to
about 2.15 by the addition of 43.75 grams of 0.5 M HNO.sub.3. The
EEPO solution was added via a low flow VWR peristaltic pump at a
rate of 1.36 grams per minute (or a total time of 102 minutes) to
the toner slurry at room temperature. The toner was then stirred
for an extra hour at room temperature after the addition of EEPO.
Subsequent to one hour of stirring, the pH of the toner slurry was
increased to 11.33 with 51.09 grams of 1 M NaOH and left to stir at
450 rpm for another hour. The toner was then retained overnight at
ambient temperature; then the surface treated toner was then
filtered and washed three times. The filtercake resulting was then
resuspended to approximately 25 percent by weight solids and freeze
dried. The pH of the filtrates was always greater than 7.5 and
showed no sign of precipitated EEPO; and it is believed that all
EEPO polymer was transferred to the toner surface. The resulting
toner was comprised of 85 percent of the sodio-sulfonated
polyester, 9 percent carnauba wax dispersion and 6 percent by
weight of black REGAL 330.RTM., FLEXIVERSE.TM. pigment with 5
percent EEPO relative to dry toner weight deposited or coated on
the toner's surface.
EXAMPLE VI
[0091] (JC026D):
[0092] Preparation of EEPO Solution:
[0093] An aminoalkylmethacrylate copolymer of EUDRAGIT.TM. EPO
(EEPO), which was delivered as a 1.9 percent (wt/wt) solution in
deionized water (DIW), was prepared by dissolving 5.34 grams of the
EEPO in 266.83 grams of acidified water (pH=1.43 with nitric acid);
the pH of the solution was lowered to 2.05 by adding 8.38 grams of
1 M HNO.sub.3. Lowering the pH of the aqueous solution to 2 ensured
complete solubility of the EEPO polymer in the solution. The total
percentage of EEPO to toner was to equal 10 percent weight of dry
toner.
[0094] Coating Procedure of EEPO onto Surface of Polyester Toner
Particles:
[0095] The stock pilot plant toner of 85 percent sodio-sulfonated
polyester, 9 percent carnauba wax dispersion and 6 percent by
weight of black REGAL 330.RTM., FLEXIVERSE.TM. pigment
(PP-6073-EAP-R5-K6W) was treated in the lab via a pH shifting
procedure where EEPO was soluble or insoluble in an aqueous
solution depending on the pH of the aqueous solution.
[0096] A 325.01 gram quantity of the toner slurry (16.4 percent by
weight solids in 83.6 percent mother liquor) of 85 percent of the
above sodio-sulfonated polyester, 9 percent carnauba wax dispersion
and 6 percent by weight of black REGAL 330.RTM., FLEXIVERSE.TM.
pigment was separated from its mother liquor via decanting, and
then stirred in a 1 liter glass Erlenmeyer flask on a stir plate at
450 rpm. The pH of the toner slurry was lowered from 5.58 to 2.05
by the addition of 44.83 grams of 0.5 M HNO.sub.3. The EEPO
solution was added via a low flow VWR peristaltic pump at a rate of
1.46 grams per minute (or a total time of 188 minutes) to the toner
slurry at room temperature. The toner was then stirred for an extra
hour at room temperature after the addition of EEPO. Subsequent to
one hour of stirring, the pH of the toner slurry was increased to
11.43 with 62.36 grams of 1 M NaOH and left to stir at 450 rpm for
another hour. The toner was then retained overnight at ambient
temperature; then the surface treated toner was filtered and washed
three times. The filtercake resulting was then resuspended to
approximately 25 percent by weight solids and freeze dried. The pH
of the filtrates were always greater than 7.9 and showed no sign of
precipitated EEPO; it is believed that all EEPO polymer was
transferred to the toner surface. The resulting toner was comprised
of 85 percent of the sodio-sulfonated polyester, 9 percent carnauba
wax dispersion and 6 percent by weight of black REGAL 330.RTM.,
FLEXIVERSE.TM. pigment with 10 percent EEPO relative to dry toner
weight deposited or coated on the toner's surface.
[0097] Triboelectric Charging Evaluation of Preliminary Cyan
Toners:
[0098] The data in Table 1 highlights the triboelectric charging
results for the four preliminary EA (Emulsion/Aggregation)
polyester toner samples, three of which were surface-treated with
EEPO with the other two being the untreated parent toners (control
samples). The opposite sign triboelectric charge levels were
observed in all three treated toners in both the A-zone or
28.degree. C./85 percent relative humidity (RH) zone and the C-zone
or 10.degree. C./15 percent relative humidity (RH) zone. The
carrier used for the parent toner measurements was a 35 micron
solution coated carrier designated EFC35B with 1.62 percent by
weight of a composite of a polymer of a crosslinking acrylic resin
(THERMOLAC.TM. RF-17), 0.17 percent by weight of carbon black
(VULCAN.TM. 72) and 0.20 percent by weight of melamineformaldehyde
resin powder (EPOSTAR.TM. S). The toners were mixed with the
carrier and conditioned overnight (about 18 hours) at 15 percent
and 85 percent RH and charged for 60 minutes using a Turbula mixer.
The toner concentration in the developer was 5 parts per hundred.
Triboelectric charge was measured using a charge spectrograph. The
number assigned for the charge represents the midpoint of the
charge distribution in millimeters displacement from the zero
charge line. A desired triboelectric charge for both the A (the
charge levels at 85 percent RH) and C-zone (the charge levels at 15
percent RH) is about 4 to about 20 .mu.C/grams while the RH ratio
for the toner would be equal to or greater than about 0.4.
Preliminary results indicated excellent toner charge reversal from
negative to positive triboelectric charge.
[0099] The triboelectric charging results for the nontreated toners
and EEPO surface treated toners are shown in Table 1. The surface
treated toners exhibited up to a 4 .mu.C/grams charge reversal in
the charge levels at 85 percent RH and up to 16 .mu.C/grams charge
reversal in the charge levels at 15 percent RH, thereby causing the
RH sensitivity (the ratio of charge level at 85 percent RH versus
15 percent RH) to improve by a factor of 6 to 11.
1TABLE 1 Tribocharging Results For Preliminary Experiments of
Toners Surface Coated With EUDRAGIT .TM. EEPO and Their
Corresponding Controls q/m q/m .mu.Coul/g .mu.Coul/g EEPO Surface
(85 percent (15 percent q/m Toner ID Treatment RH) RH) RH ratio
VF173 None -0.67 -20.6 0.03 VF231 None -1.22 -19.1 0.06 VF246 3
percent EEPO +4.41 +12.8 0.34 VF261 3 percent EEPO +3.08 +14.4 0.21
VF258 3 percent EEPO +3.08 +15.9 0.19
[0100] Triboelectric Charging Data:
[0101] The data presented in Table 2 highlights the opposite sign
triboelectric charge levels, in both the 15 percent and 85 percent
RH zone, and RH ratio for toners in Examples I through VI treated
with various levels of EEPO, compared to the reference toner VF173
and JC003G of the Comparative Examples 1 and 2. The opposite sign
triboelectric charge levels are illustrated in all six treated
toners, in both the A-zone or 28.degree. C./85 percent relative
humidity (RH) zone and the C-zone or 10.degree. C./15 percent
relative humidity (RH) zone. The carrier used for the parent toner
measurements was a 35 micron solution coated carrier designated
EFC35B with 1.434 percent by weight of a composite of a polymer of
crosslinking acrylic resin (THERMOLAC.TM. RF-17), 0.366 percent by
weight of carbon black (VULCAN.TM. 72) and 0.200 percent by weight
of melamine-formaldehyde resin powder (EPOSTAR.TM. S). The toners
were mixed with the carrier and conditioned overnight (about 18
hours) at 15 percent and 85 percent RH and charged for 60 minutes
using a Turbula mixer. The toner concentration in the developer was
5 parts per hundred. Triboelectric charge was measured using a
charge spectrograph. The number assigned for the charge represents
the midpoint of the charge distribution in millimeters displacement
from the zero charge line. The desired triboelectric charge for
both the A (the charge levels at 85 percent RH) and C-zone (the
charge levels at 15 percent RH) was about 4 to about 20
.mu.C/grams; while the desired A/C or RH ratio for the toner is
equal to or greater than 0.4. Preliminary results indicated
excellent charge reversal from negative to positive triboelectric
charging. The triboelectric charging results for the nontreated
toners and EEPO surface treated toners are shown in Table 2. The
surface treated toners exhibited up to a 5 .mu.C/gram charge
reversal in the charge levels at 85 percent RH and up to 20
.mu.C/gram charge reversal in the charge levels at 15 percent RH,
thereby causing the RH sensitivity (the ratio of charge level at 85
percent RH versus 15 percent RH) to improve by a factor of about 2
to about 7.
2TABLE 2 Tribocharging Results of Toners Surface Coated With EEPO
and Their Non-Treated Counterparts q/m, q/m, .mu.Coul/g .mu.Coul/g
(85 (15 q/m EEPO Surface percent percent RH Toner ID Treatment RH)
RH) ratio Comparative Example 1 None -1.8 -26.4 0.07 (VF173)
Comparative Example 2 None -1.1 -15.6 0.07 (JC003G) Example I
(VF246) 3 percent EEPO +5.1 +12.4 0.41 Example II (JC003B-2) 1
percent EEPO +1.5 +12.2 0.12 Example III (JC003C-2) 3 percent EEPO
+2.0 +12.9 0.16 Example IV (JC003E) 7 percent EEPO +2.8 +20.6 0.14
Example V (JC026A) 5 percent EEPO +2.5 +7.1 0.35 Example VI
(JC026D) 10 percent EEPO +3.1 +6.4 0.48
[0102] While particular embodiments have been described,
alternatives, modifications, variations, improvements, and
substantial equivalents that are or may be presently unforeseen may
arise to applicants or others skilled in the art. Accordingly, the
appended claims as filed and as they may be amended are intended to
embrace all such alternatives, modifications variations,
improvements, and substantial equivalents.
* * * * *